Laboratory demonstration apparatus



y 1952 F. E. LAMBERT, JR 2,596,034

7 LABORATORY DEMONSTRATION APPARATUS Filed Sept. 3, 1949 FIG. 2 FIG. 3

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- 50o 40o A/%%Z 3OO 200 25 IOO23 L// LZZ'JJ)) lo I 300 I '5 INVENTOR. FRANK E. LAMBERT, JR.

ATTORNEY Patented May 6, 1952 LABORATORY DEMONSTRATION APPARATUS Frank E. Lambert, Jr., Atlanta, Ga.

Application September 3, 1949, Serial No. 113,953

1 Claim. 1

This invention relates to a combustion jar and more particularly .to a combustion jar used in laboratory experiments and classroom demonstrations for the determination of the amount of oxygen in the atmosphere.

One of the most practical methods of demonstrating to students that oxygen comprises a certain percentage of a given volume of confined air is to replace that amount of oxygen in the iven volume of air by some visible substance such as water. This is best accomplished by confining the chosen volume of air in a transparent container having an indicated level of water, combining the oxygen by combustion with some substance which is soluble in water, and then permitting additional water to flow into the container to occupy the space previously occupied by the oxygen thereby changing the initial level of the water which is visible to the students.

Heretofore it has not been possible to realize the best possible results from the experiment due to the inadequacy of the equipment available. Since oxygen occupies approximately by volume of the volume of air, it is most desirable to have the level of the water rise at the conclusion of the demonstration to indicate this proportion. The combustion jars of the prior art have not provided a suitable construction whereby the combustible material can be ignited inside the container and then the container quickly closed, nor do the prior art devices provide suitable construction to permit an actual effective demonstration to student classes and the like.

It is an object of this invention to provide a combustion jar which may be quickly and easily rendered from an open to a closed condition.

Another object of the invention is to provide a combustion jar constructed to give maximum visibility to the actions within the jar and to the indications of the results.

Another object of this invention is to provide a combustion jar which may be rendered substantially pressure tight in a minimum of time.

A further object of this invention is to provide an apparatus for the determination of the amount of oxygen in air comprising a combustion jar and a new and novel combustion boat suspended inside the combustion jar.

It is also an object of this invention to provide a combustion boat for suspension inside the combustion jar constructed to prevent the sides of the combustion jar from interfering with the burning process.

It is also an object of this invention to provide a combustion jar with accurate and legible graduations.

Other and further objects and advantages of my invention will be apparent from the following description taken in conjunction with the accompanying drawings in which like characters 2 of reference designate corresponding parts throughout the several views, and wherein:

Fig. 1 is a front elevation of my combustion jar with the top lid removed therefrom.

Fig. 2 is a front elevation of the top lid for the structure shown in Fig. 1.

Fig. 3 is a horizontal cross-sectional view along the line 33 of the structure shown in Fig. 6.

Fig. 4 is a fragmentary horizontal cross-sectional view of the top lid of Fig. 2 mounted in place on the structure of Fig. 1.

Fig. 5 is a fragmentary top plan view of the structure of Fig. 1.

Fig. 6 is a bottom plan view of the structure shown in Fig. 2. i

Fig. 7 is a top plan view of my combustion boat.

Fig. 8 is a horizontal cross-sectional view taken on the line 88 of Fig. 7.

My combustion jar I0, which may be constructed from glass, plastic or a similar material, comprises an elongated tubular central body portion I I terminating in an upper open neck I2 and a lower open neck l3 which is of larger diameter than the upper neck I2. The thickness of the body portion l I and the neck portions l2 and I3 may be varied according to the characteristics of the material from which they are constructed. Protruding circumferential shoulders I4 and I5 are formed on the combustion jar at the junctions of the central body portion I I and the neck .portions I2 and I3, respectively.

An upper lid I6 which is of an open disc shape has an annular indentation on the upper inside face at I! into which fits a rubber, or like material, ring type gasket I8 having depending sealing flanges I9 and I9. The inside circular face of the lid I6 has'formed thereon three sets of circumferentially spaced inwardly protruding threads 20 and each set of the embodiment chosen for illustration comprises three such threads 20, inclined to the horizontal and vertically spaced apart.

The upper neck I2 has formed thereon three sets of spaced outwardly protruding threads 2I .which are identical to the threads 20 formed upon the upper lid I6 and are equally spaced around the circular face of the neck portion in the same proportion as the threads 20 are spaced upon the upper lid I6. The threads 20 and the threads ZI cooperate when placed together to form what is commonly known as a breech type lock or a quick lock. A tight seal between the .upper neck I2 and the lid l6 may be formed quickly and easily by placing the open portion of lid I6 over the neck I2, pushing the lid I 6 down to force the gasket I'I against the lip of the neck, and giving the lid I6 a slight twist causing threads 20 to interlock with threads 2|. When the lid I6 is in position, as shown in Fig. 4, the lower edge of the lid fits against the shoulder 44 forming a lower seal while the gasket I! and .always indicates larger in size in order to fit the larger neck portion [3. Lower lid 22 and its corresponding neck 13have breech lock threads (not shown) formed thereon to cooperate in the same manner as the threads 20 and 2| of lid l6 and neck portion [2. The lower lid 22 also has a circumferential indentation on the upper inside face receiving a gasket the same as upper lid I6.

Arranged along the longitudinal center of one side of my combustion jar are vertically spaced graduations from millilitres, which represents the water line, upwards to 900 millilitres and downward to 300 millilitres. 14 represents the 1000 millilitre mark and this may be noted in writing on the jar. There is also an auxiliary water line immediately beneath the 0 water line. I

For the purpose of illustration in the particular embodiment of Fig. 1, the lower lid 22 is tightly in place and water has been placed in my combustion jar up to the 0 water line. Floating on the surface of the water is my novel combustion boat 23 which comprises a cylindrical cup 24 having a protruding bumper ring 25, as

seen in Fig. 7, formed on the lower outside peripheral surface thereof. This combustion boat 23 isa container for the substance which is burned to consume the oxygen, and the ring 25 prevents the cup 24 from contacting the sides of the jar l0 and thereby extinguishing or interfering with the burning process. 7

In use, my combustion jar is prepared for its operation by sealing the bottom neck l3 with the bottom lid 22 and placing water in the jar until the level of the water is even with the 0 water mark on the central portion I l. The combustion boat 23 is placed on the surface of the water and a suitable substance such as phosphorus is placed in the cup 26. The jar is now in the condition illustrated in Fig. 1.

A heated wire is placed through the open neck !2 down until it is near the phosphorus in the boat 25, the upper lid 0 is poised near the neck !2, the heated wire is touched to the phosphorus and quickly removed from the open neck, then the upper lid 16 is quickly placed and tightened on the neck 12 by means of the breech lock threads 28 and 2i.

As soon as all the oxygen has burned from the air above the water level, the jar is placed in a pan of water, the lower lid 22 is removed,

and wateris permitted to flow up into the jar.

Because of my novel construction, the level of the water as it rises may be readily observed by onlookers and readings may be taken as the level or" the water passes the various graduations. Due to the accuracy of my construction the water approximately 20% oxygen in the air.

Further, the handling or tilting of the jar during the burning process does not affect the results of the demonstration since the boat 23 rides on the surface of the water and the bumper ring 29 eliminates any interference from the sides of the jar. V

The particular construction of the upper lid 13 and the lower lid 22 permits a pressure tight closure to be formed in a minimum of time. Though the upper lid i9 is shown, it is obvious The upper shoulder that a heavy rubber stopper may be substituted and the auxiliary water line permits compensation for the amount 'of air displaced'above the water line by the protruding end of the rubber stopper.

It will be obvious to those skilled in the art that many modifications and changes may be made in the embodiment shown and described without departing from the scope of my invention as defined in the appended claim.

I claim:

Laboratory demonstration apparatus for determining the oxygen content in air'comprising in combination a transparent hollow combustion jar adapted to contain a liquid and a fioatable combustion boat located within ,said jar and adapted to float on said liquid, said combustion jar including a graduated main body portion of wide cross-section with respect to its length to' enable accommodation of said boat and confine relatively large volumes of gas in a relatively short jar,,wide mouth circular openings located at the upper and lower ends of said body por-' tion, said openings having a smaller cross-section than said main body portion and of sunicient cross-section to accommodate insertion of said boat through said openings into said jar; and removable breech type closure means on said upper and lower openings; said fioatable combustion boat being cup shaped and having afiixed thereto a circular bumper means which projects beyond the outer surfaces defined by the boat to prevent physical contact between/the body portion of said jar and the combustion boat, said boat and bumper means being of smaller cross-section than the upper and lower openings of the combustion jar.

FRANK E. LAMBERT, JR.

' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1 358,008 Baker Feb. 22, 1887 484,210 Ludde -1 Oct. 11, 1892 857,308 Sanford June 18, 1907. 1,206,192 Bacharach Nov. 28, 1916 1,431,618 Aderer Oct. 10, 1922 1,448,901 Moreland Mar. 20, 1923 1,577,020 Hammer Mar. 16, 1926 1,755,944 Adams Apr. 22, 1930 1,882,278 Francyk Oct. 11, 1932 2,092,192 Von Till Sept. 7, 1937 2,142,846 Howe -1 Jan. 3,.1939 2,383,098 Wheaton, Jr. Aug. 21, 1945 FOREIGN PATENTS Number Country Date 34,552 Austria 1 Sept. 25, 1908 373,984 Germany Apr. 18, 1923 592,429 Germany Feb. 7, 1934 798,396 France m May 15, 1936 OTHER REFERENCES Babor and Lehrman, General College Chemistry, 2nd ed, page 152, 1940. Thomas Y. Crowell Dennis, Gas Analysis pages 181484, 1929, MacMillan Co., N. Y. C.

Cooke, Journal of Chemical Education,

pages 105, 106. Vol. 6, No. 1, Jan. 1929. 

